Does Deployment-Related Military Sexual Assault Interact with Combat Exposure to Predict Posttraumatic Stress Disorder in Female Veterans?

The objective of the present research was to expand upon previous findings indicating that military sexual trauma interacts with combat exposure to predict PTSD among female Iraq/Afghanistan-era veterans. Three hundred and thirty female veterans completed self-report measures of combat experiences, military sexual assault (MSA) experiences, and PTSD symptoms as well as structured diagnostic interviews for PTSD. A significant strength of the present research was the use of PTSD diagnosis as an outcome measure. Consistent with prior research, both combat exposure and MSA were significant predictors of PTSD symptoms (linear regression) and PTSD diagnoses (logistic regression). Specifically, participants who experienced deployment-related MSA had approximately six times the odds of developing PTSD compared to those who had not experienced deployment-related MSA, over and above the effects of combat exposure. Contrary to expectations, the hypothesized interaction between MSA and combat exposure was not significant in any of the models. The low base rate of MSA may have limited power to find a significant interaction; however, these findings are also consistent with other recent studies that have failed to find support for the hypothesized interaction. Thus, whereas the majority of available evidence indicates that MSA increases risk for PTSD among veterans over and above the effects of combat, there is presently only limited support for the hypothesized MSA x combat interaction. These findings highlight the continued need for prevention and treatment of MSA in order to improve veterans' long-term mental health and well-being.